Abstract:
Cyanobacterial harmful algal blooms frequently occur in drinking water sources around the world due to eutrophication as a result of antrophogenic activities. Their presence in water is a potential threat because some species of cyanobacteria can produce and release potent toxic compounds (cyanotoxins), such as hepatotoxins, neurotoxins, and dermatotoxins.

New biosensor monitors water quality

Germany | Posted on January 9th, 2013

Among hepatotoxins, microcystins (MCs) are the most frequently reported cyanotoxins and MC-LR is the most commonly occurring congener of MCs worldwide as well as in the USA. The World Health Organization (WHO) has proposed a provisional concentration limit of MC-LR in drinking water of 1 μg L-1. Therefore, there is a need for techniques to monitor MC-LR in various sources of water.

Recently, Prof. Dionysiou's group at the University of Cincinnati (UC) in the USA and his collaborators (UC and USEPA, Cincinnati, USA; and NCSR Demokritos, Athens, Greece) developed a multi-walled carbon nanotube (MWCNT)-based electrochemical biosensor to monitor MC-LR in sources of drinking water supplies.

They reported the formation of oxygen-containing functional groups on the MWCNT surface following electrochemical functionalization in alkaline solution. The performance of the MWCNT array biosensor demonstrated a marked increase of the electron-transfer resistance upon antibody conjugation. The biosensor's electron-transfer resistance showed a linear dependence on the MC-LR concentration ranging from 0.05 to 20 μg L-1. The sensing performance of the biosensor at low MC-LR concentration allows monitoring of this cyanotoxin well below the drinking water provisional concentration limit of 1 μg L-1.